It would be much more efficient if you can draw predecessor links in the gantt chart default as rubber.
Let me try to explain:
Lets say I have a planning with three tasks. Task 3 starts when task 2 is finished and task 2 starts when task 1 is finished.
Task 1 occupies week 1
Task 2 occupies week 3
Task 3 occupies week 5
If I simply drag the arrows between the tasks they get created as hardness=strong. This means that that task 2 moves to week 2, and task 3 moves to week 3. After that I have to manually edit the predecessors from hardness=strong to hardness=rubber. After that I can move task 2 and 3 to there planned week (3 and 5). This is a lot of extra work. If you have a complex ganttchart and draw one link, the whole chart can be corrupted (tasks move to the wrong date)
If I could drag the arrows as rubber in the first place (by setting a default hardness to rubber or holding down some key ....) this would be much more efficient.
Hopefully this will be included in a future release of this great product.